Facile synthesis of an ultramicroporous MOF tubular membrane with selectivity towards CO(2)

International audienceA substituted imidazolate-based MOF (SIM-1) membrane has been crystallized in situ on a tubular asymmetric alumina support that can be exploited for gas separation through preferential adsorption

Construire des pratiques participatives dans les bibliothèques

Participer et faire participer les citoyens, les publics ? Qui participe, comment et jusqu’où ? Que devient le professionnel avec ce nouveau paradigme ? Comment emporter l’adhésion des habitants ? De plus en plus de bibliothèques s’engagent activement dans la participation, selon des modalités et des niveaux d’implication variés. Cette mutation des pratiques renouvelle les réflexions engagées autour des publics : ne plus seulement mettre les publics au centre du cercle mais créer les conditions pour les accompagner à dessiner ce cercle. Empowerment, co-construction, crowdsourcing, savoirs partagés, participation démocratique… cet ouvrage permet de clarifier les notions attachées aux dynamiques participatives et propose un cadre de réflexion qui permettra aux bibliothécaires de construire leurs modes d’action entre PirateBox, BiblioRemix, comités d’usagers, design de service et autres formes de projets participatifs. Organisé en trois parties - Repenser la bibliothèque ensemble, Partager les savoirs, Décider ensemble ? – ce volume présente également un ensemble de témoignages de praticiens du sujet, en France et aux États-Unis, de la préfiguration d’une bibliothèque à son réaménagement, en passant par la création de plateformes collaboratives et de nouveaux services. L’expérience d’un musée et l’aventure d’un centre social viennent enrichir le panorama

Synthèse de nouvelles zéolithes en vue d'applications en déparaffinage

Dans le cadre du développement de nouveaux catalyseurs acides à base de zéolithes destinés au déparaffinage par hydroisomérisation de coupes pétrolières lourdes, plusieurs études ont permis de montrer qu'un très bon candidat serait un catalyseur composé d'une zéolithe aluminosolicate (Si/Al~15-30) présentant un système monodimentionnel de pores délimités par des cycles à dis tétraèdres.MULHOUSE-SCD Sciences (682242102) / SudocSudocFranceF

External Surface of Zeolite Imidazolate Frameworks Viewed Ab Initio: Multifunctionality at the Organic−Inorganic Interface

The external surface sites of zinc based zeolite imidazolate frameworks (ZIFs) is investigated by cluster density functional theory calculations, which reveal a great variety of sites. Their stability as a function of temperature and pressure is resolved, thanks to a thermodynamic approach. Low-coordinated zinc cations Zn_II and Zn_III, which can play the role of Lewis acid sites, are stabilized over a wide temperature range. Brønsted acid sites (NH groups), basic sites (N⁻ extremities), as well as OH groups and hydrogenocarbonates (monodentate mainly, but also bidentate) are also stable. Their calculated vibrational feature is consistent with high-frequency vibrations observed in experimental spectra of ZIF-8 materials reported in the literature. This coexistence of groups of various expected reactivity opens perspectives to multifunctional catalysis at the external surface of ZIF-8

Synthesis of hollow Y zeolites

SSCI-VIDE+ING+CPG:DFA:ATUNational audienceNon

Synthesis of hollow Y zeolites

SSCI-VIDE+ING+CPG:DFA:ATUNational audienceNon

Synthesis of encapsulated nanoparticules in hollow beta zeolite

SSCI-VIDE+ING+AMP:ATU:DFAInternational audienceHollow Zeolites with encapsulated nanoparticles (NPs) have recently attracted much attention due to their remarkable advantages as catalytic nanoreactors compared to bulk zeolite supports. Although zeolite shells provide protection against sintering and poisoning, they are usually polycrystalline, fragile and relatively thick. Recently, we succeeded to prepare a series of metal NPs in single hollow zeolite crystals with MFI-type structure by selective dissolution of bulk crystals preliminary loaded with metal precursors (1). The MFI nano-boxes showed remarkable size selectivity in the hydrogenation of toluene but their activity is limited to small substrates because of the small pore opening of the framework (approx.. 0.55 nm) (2). So far, all examples of NPs in hollow single crystals deal with zeolites of MFI-type structure (ZSM-5 and Silicalite-1).In the present work, we report for the first time the preparation of hollow beta zeolite single crystals containing platinum nanoparticles. Beta nano-boxes are prepared by dissolution/recrystallization of CIT-6 crystals, which is a zincosilicate exhibiting the same *BEA structure, based on a modified method (3).Depending on the preparation method, Pt NPs can be located either (i) on the external surface, (ii) in the walls or (iii) inside the cavity of the crystals (4, 5). Materials have been characterized by X-ray diffraction, N2 adsorption and electron microscopy (TEM and SEM). High resolution tomography has also been used to confirm the location of Pt NPs as well as their narrow particle size distribution. Besides structural characterization, the presentation will illustrate the potential of such materials in catalysis by model reactions such as the hydrogenation of substituted aromatics with different sizes. Catalytic results will be discussed in light of adsorption and diffusion studies.(1) S. Li, A. Tuel, J.-L. Rousset, F. Morfin, M. Aouine, L. Burel, F. Meunier, D. Farrusseng, ChemNanoMat. 2(6) (2016) 534.(2) S. Li, A. Tuel, D. Laprune, F. Meunier, D. Farrusseng, Chem. Mater. 27 (2015) 276.(3) K. Iyoki, K. Itabashi, T. Okubo, Chem. Asian J. 2013, 8, 1419.(4) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.460 (2016).(5) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.461 (2016)